# computer PS and ohm law

Discussion in 'Electronic Basics' started by Wandy, Dec 18, 2003.

1. ### WandyGuest

Hi

I am trying to use an atx pc power supply without wasting your time going to
details

There are two type of connectors:
1- One is 10pins x2 raw female connector
2- 3or4 with one raw of four pins (these you hook them to HD, floppy D, etc…

I think all I need is the first one

Green should be connected to ground, now the question
Some suggest using small resistor, where do I hook it

If I need 12V which do I use? Yellow and ??
If I need 5V which do I use? Red and ??
If I need 3.3V which do I use? Orange and ??

can i use ohm law if using the 12V, would it be ok to use 10wat 2Ohm
resistor so i get 6Amp and so on.

Jed

2. ### Ross MacGuest

Hi

I am trying to use an atx pc power supply without wasting your time going to
details

There are two type of connectors:
1- One is 10pins x2 raw female connector
2- 3or4 with one raw of four pins (these you hook them to HD, floppy D, etc.

I think all I need is the first one

Green should be connected to ground, now the question
Some suggest using small resistor, where do I hook it

If I need 12V which do I use? Yellow and ??
If I need 5V which do I use? Red and ??
If I need 3.3V which do I use? Orange and ??

can i use ohm law if using the 12V, would it be ok to use 10wat 2Ohm
resistor so i get 6Amp and so on.

Jed
That should be fine but make sure to use the power equation P=IE so you pick
the correct wattage! It seems to me that 6amps at 12 volts is going to need
at least a 72 watt, or the next size up, resistor....Why don't you just fuse
it if you are worried about overdrawing the supply.
That resistor would be quite large......Probably a 2 ohm 100 watt!!
For the wire colors...I would just do a Google search...

3. ### Ross MacGuest

Hi

I am trying to use an atx pc power supply without wasting your time going to
details

There are two type of connectors:
1- One is 10pins x2 raw female connector
2- 3or4 with one raw of four pins (these you hook them to HD, floppy D, etc.

I think all I need is the first one

Green should be connected to ground, now the question
Some suggest using small resistor, where do I hook it

If I need 12V which do I use? Yellow and ??
If I need 5V which do I use? Red and ??
If I need 3.3V which do I use? Orange and ??

can i use ohm law if using the 12V, would it be ok to use 10wat 2Ohm
resistor so i get 6Amp and so on.

Jed
One other thing here...if you are attempting to use this resistor as a
current limiting device the calculation would be much different. Since the
drop accross the resistor would depend on the internal resistance of the
load. If you are just putting the resistor accross the supply, than 72 watts
is it. If the resistor has .1 volts accross it then you would only need a 10
watt resistor....I wasn't very clear on what you were trying to do here!

4. ### Ken TaylorGuest

Hi Jed.

What are people suggesting you use a resistor for? You *may* need to put a
minimum load onto the +5V output so that it will regulate properly (or maybe
even turn on at all). However you do not need a resistor to draw a
particular current - if your load will draw 6 Amps, it will draw 6 Amps (as
long as the power supply can cope).

One or more of the wires on the connector(s) will go to ground, which you
will find will connect with the blacks on the FDD/HDD cables - use a
multimeter to find out which one(s) this is. The outputs are between the
various outputs and this earth.

Cheers.

Ken

5. ### Richard CrowleyGuest

Who suggested it? For what?

When I searched for "atx pinout color", I found many
web pages that have exactly the info you are asking for.
This question would have been answered quicker by
learning to use web search engines than by posting it
here,.

says that you directly ground pin 14 (the green wire) to start
the power supply.

No mention of any resistor (unless it is to provide the

Note that color codes are not necessarily standard.
Pin connections ARE standard and you should work
back from those.
Black is usually the common ground for ALL voltages.
Huh? What are you trying to do?

6. ### DarkMatterGuest

For somebody that claims to have been on the net as long as you
have, you don't know a damned thing about how to quote previous texts.

Get a real news reader, ya retard.
]
Outhouse Express ain't it. Fucking retards, all of you OE users..

7. ### DarkMatterGuest

Then... your LAME ass double posted it. Oh boy... you really ARE
experienced on the net... Not!

You aren't a "years experienced" net user, you are a fucking net
twit, just like I said you were, the first time I did... Months ago.

8. ### DarkMatterGuest

Absolutely true.

9. ### The little lost angelGuest

Usually on the +5V. This is because cheap ATX PSU will not work
properly without a minimum load on the +5V. More expensive ones, I
don't have any problem starting them and using them without a +5V

However, most ATX PSU cross regulate on the +5V and +12V so if you are
going to draw quite a bit of power on the +12V, you will need a load
on the +5V to keep the +12V voltage up.
All with the black ground wires.
6 Amps x 12 = 72 Watts, that 10W resistor will burn out pretty quickly
Or parallel connect 10x 20 Ohmz 10W.

You might wanna look at some of these things I've been looking at for
that kind of purposes.

http://www.brakingresistor.com/metal.htm

I'm not recommending them as good or bad, I don't know. But these
things appear to be only ones suitable for high loads on the +12V.

--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me
Standard HTML, SHTML, MySQL + PHP or ASP, Javascript.
If you really want, FrontPage & DreamWeaver too.
But keep in mind you pay extra bandwidth for their bloated code

10. ### Ross MacGuest

Our childish Usenet Prick is back!.....You must have something better to do
than this!

11. ### Ross MacGuest

I don't see a double post here....drunk again and seeing double....You
really should lay off the sauce kid!

12. ### Rheilly PhoullGuest

Hi

I am trying to use an atx pc power supply without wasting your time going to
details

There are two type of connectors:
1- One is 10pins x2 raw female connector
2- 3or4 with one raw of four pins (these you hook them to HD, floppy D, etc.

I think all I need is the first one

Green should be connected to ground, now the question
Some suggest using small resistor, where do I hook it

If I need 12V which do I use? Yellow and ??
If I need 5V which do I use? Red and ??
If I need 3.3V which do I use? Orange and ??

can i use ohm law if using the 12V, would it be ok to use 10wat 2Ohm
resistor so i get 6Amp and so on.

Jed

All the power and volts stuff aside, you have to ground the "Power good" pin
on the long connecting plug. Its pin #14, most likely green.
go here, it's a good source !
http://www.hardwarebook.net/connector/power/atxpower.html

13. ### DarkMatterGuest

Damn..... he actually quoted correctly this time!

14. ### DarkMatterGuest

Hey, dipshit... Yeah YOU. You replied to the guy twice, or you
posted the reply twice. Usenet doesn't make mistakes. YOU did.

Shall I provide posting ID numbers, ya retard?

15. ### Ross MacGuest

Time for you to go back where you came from... alt.drugs.pot ....keep
swallowing the bong water boy!

16. ### Ross MacGuest

Uhhh....the ID numbers are different as are the posts...
I just saw you quadruple post alt.engineering.electrical (under you own
definition anyway!)...
You really are a sick individual... You expect everybody to post exactly
like you do with exactly the same newreader.... You sure live a pathetic
life! I would still recommend a few good 12 step programs for you... One for
anger management and the others for your drug and alcohol problem!
You mentioned I had only been on the newsgroups for a few months....not
true....I have been away for a few years but had a copy of Agent back in 95
and used to be quite active. My first access to the internet was with the
old unix command prompt. I guess you just do a google search and begin the
wild and unsubstantiated. I have seen posts of you claiming to be a
descendant of 2 presidents, having put up many a ham radio tower, delivering
medical marijuana, you have a conformal coating fetish, you are a circuit
board expert who never was in the business for even a day and let's not
forget that you are the biggest and baddest with the largest prick . Now
that I believe since you are ALL DICK!. You even posted the Apollo mission
to the moon was hoax!.
I suspect there are a couple hundred engineers that might like to talk to
you about that piece of brilliance!
So if anyone here is a "net twit".....well look in the mirror "Don'tMatter"
and stop swallowing the bong water doper boy!

17. ### DarkMatterGuest

Look, dipshit, you replied to the guy, but you posted the reply
twice.

Nothing you can do will change that fact.
No. You didn't. By any definition. You didn't *see* me do a
goddamned thing, boy.

No, dipshit. I expect you to suck up the same scrutiny that your
lame ass heaps out. Except that you don't know what the **** you are
talking about, nd you still feel the 12 year old need to post up a
retarded song occasionally. How mature.... not.
What anger? What drugs and alcohol? You're a goddamned idiot.
No. I said that you only knew about headers for a few months, you
fucking retard.
We fdon\t need your "I was the first AOL customer" retarded baby
bullshit again, dipass.
I am. I'd bet that you cannot make such a claim. My blood makes
the claim for me.

You couldn't be any more retarded.
I have.
Nope. I actually farm the stuff. I am a care provider, not a
delivery boy, dipshit. Big difference.
No, I use conformal coatings on JHV assemblies, because it seals out
moisture in the PCB, and gives the assembly years more life, and
reliability.

Could you be any more retarded? I think not.
When you integrate 13kV capacitors into the sub-surface layers of a
PCB assembly using polymide insulative layers, and eliminate the cost
of 6 or 8 capacitors in a 50M piece order, saving the company a half
million dollars for each penny saved, you can brag about it. Until
then, you are just another little punk that used to crank a few
boards.

To you.... sure...
No, dipshit. I did not. I have always posted AGAINST those
retards, just like I post AGAINST your lame, retarded ass.

YOu are a fucking retard boy. I watched every launch. I have
models of the Saturn 5 booster, and Apollo mission modules.

You're a fucking idiot. I never posted against the moon missions,
dipshit.

Put up the post ID, fuckhead. I'll prove you wrong.

I can also cite years worth of posts in other groups that show I put
down the hoax retards, just like I put down your retarded ass.
You are as bad as any of those cranks ever could be.

You failed miserably the last time you "searched up" my posts, and
you did again here, dipshit. Get a clue.
You're an idiot. You're a dumbfuck. You are so stupid, you can't
even tell what I have or have not posted. That is pretty bad,
considering that it is public record. You need to upgrade your
ability to waste time, digging up "my" posts on the net. You are
doing a sad job of it so far.

You be 'tard, boy.

18. ### Keith R. WilliamsGuest

news.ops.worldnet.att.net>,
says...
Back? The childish 43YO is not back. The prick is still here!
....and hasn't learned a single thing.

It's amazing that one can survive into the forties with such a
chip on the shoulder and nasty attitude. ...not to mention
paying the rent with no knowledge. Though there is only one
button on the fry-o-lator.

19. ### Keith R. WilliamsGuest

news.ops.worldnet.att.net>,
says...
Hey, that was me he quad-posted to. ...and I feel cheated! His
record is seven!

Well, duh!
Good grief no! DimBulb doesn't like multiple postings! ;-)

<snipped much DimBulb trueisms>

DimBulb has a *long* history (a.k.a. fat bytestard) of being an
anti-social moron.

20. ### Ross MacGuest

Dimbulb just makes it up as he goes...I post twice and he bitches, then he
will see his antisocial rants and his ridiculous stands....not to mention
what those of us have seen in this newsgroup! And like I have always said,
this guy is a substance abuser...he claims to grow medical marijuana..
yeah...and also claims he never uses...Uhhhh...just read the above post...I
think he makes a pretty good case for a 12 step program! Ole TardMatter is
swallowing the bong water again.....
You have to wonder what he is like to work with....can you see him in a
meeting jumping up from his stroller and yelling....
You dipshit...you retard...you are and idiot! ( I could go on, but we all
know the rest of his rants)
He also claims in the above post that he was responsible for buried
capacitance in innerlayers of circuit boards...another grandiose claim....I
know the person that developed that, I worked for the company that held the
patent and he had nothing to do with it! And, the circuit board
manufacturers are the ones who build it not "ConformalBoy". Perhaps he wants
bragging rights for specing it out....Now, that would REALLY impress me.
Then he tells me, I cranked out pcb's for a living...he has not a clue what
I did in that business...but we can suffice to say, I must not have been
cranking out boards because I live on my investments!...........
Need I say more??????